initial security deposit - bank transfer or other methods

[Kosh Vokter]

How do you normally get the initial security deposit from a tenant? Getting ready to have tenants sign the lease in WA, is it okay to ask them to do a bank transfer before giving the keys after the lease is signed or is it advisable to get it in a different form - check or money order?

Does the security deposit have to be held in a separate bank account?